The principle and application purpose of oversamplesuperposition technique are discussed based on the characteristics of long wave IR detector. The effects of oversample and superposition are analyzed on the basis of PTF, and the corresponding oversamplesuperposition PTFs at different division multiples (m) are given. As m is increased, the pattern of pushingtype scan sample is varied from instantaneous single sample (m=1) to integral sample at full residence time (m is tended towards infinity). The variation of PTF is not distinct when m>4.